Chinese laser accuracy problem letters look pixalated rabbit (6090?)

[Levi Chanowitz]

Can you help me?

We always had some trouble with getting sharp letters from the Rabbit laser
We use “ Laser Engrave and Cut System (DSP) 4.0. We have a 60 watt laser.

Attached are some pictures of the problem and of the machine


Sincerely,
　
Moishe L. Chanowitz
Plaque Impact!

ta 113 (1024x768).jpgta 099 (1280x960).jpgta 101 (1024x768).jpgta 110 (1024x768).jpg

[Ross Moshinsky]

You most likely need to increase your scan gap setting and possibly slow down the machine.

[Levi Chanowitz]

it doesnt help at all. It becomes worse!
My scan gap (step interval) is.088, my speed is 400 and my power is 60

[Ross Moshinsky]

Sorry, I forgot on Chinese machines higher the gap, lower the resolution. Your scan gap should be around .05 (roughly 500dpi). I'm not sure about the speed but I believe between 400-600 is what you want.

[Levi Chanowitz]

made the scan gap .05. did not help

[Bruce Dorworth]

Silly question, but have you zoomed in and looked at the text? Is it a nice crisp edge on the file that you are sending to the laser?

Bruce

[Scott Naylor]

I have a rabbit and just engraved some romark material. I used a speed of 300 with a scan gap of .085 - using the LaserCut software. I think I could have run faster, but I only had one shot at this job and after a small test pattern, these are the values I used. I also questioned the rabbit supplier about maximum speed and was told that even though the machine will run faster, you may loose quality above a speed of 350. It's worth a try to slow down a bit.

[Levi Chanowitz]

yess! it is arial in vectors from Corel Draw

[Rodne Gold]

You need to check a few things
1) Check belt tightness and check if there is any slop in the motion system\
2) Check your material is actually not moving at all
3) Try to do the same engraving using one direction engraving only (not firing on the forward and backward scan of the head , just on forward) , if it is better then you need to set backlash compensation , this is actually a software setting to control where the laser fires for a forward scan and then a backward scan. You need a magnifying loupe to inspect the engraving .
You want something like this
-------
-------
-------
-------

and NOT this
------
...------
------
....------

(ignore the dots , they just to format the text in the post)
Backlash will change with speed , so you may need to set this for different speed values

[Joe Pelonio]

Are you sure that is laserable material? It looks like what happens when using a laser on material made for rotary engraving. It's also much deeper than it should be, normally meaning set for too much power.

[john banks]

Try 200 speed, 20% power and unilateral. Get the quality back and work up from there.

[Levi Chanowitz]

tryed all powers and all speeds and I dont get any better results

[Levi Chanowitz]

Thanks for trying to help me out
I tried to loosen and to tighthen the belts, to engrave in only one direction and I checked my engraving material, but it did not help
I finally resolved part of my problem. I noticed that my letters were not smooth. When I export it to hpgl, the curves like in the "O"turn to 12- 20 sided polygons.
When I export it to .ai, I get rounded letters. This does help alot, but still does not resolve the whole problem.

Also, what is the correct way to export to hpgl?

[Mike Null]

I don't know your software but in CorelDraw you save the file as a plt file for HPGL.

[Khalid Nazim]

I have a Chinese Laser (Shenhui) and I have always exported DXF out of Corel and then imported the file in RDCAM (Laser software). I have never faced this issue on any of my detailed work.


Regards
KN